COVID-19 changed not only the way we live but also the way we teach and prepare pre-service teachers. The purpose of this paper is to describe the shift from a conventional STEM fair to an online teaching environment prepared by elementary pre-service teachers after the closure of the educational system in Cyprus as of March 2020. We describe a 3-steps process followed for the design, development, and delivery of the STEM fair concerning the technological equipment used, the activities' adaptations made by the pre-service teachers', and the level of readiness to teach online based on the initial outcomes of the STEM fair. The brief paper concludes with practical implications and suggestions for future attempts about online teacher education.